From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5820AC7EE2C for ; Wed, 24 May 2023 14:22:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235911AbjEXOWh (ORCPT ); Wed, 24 May 2023 10:22:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229919AbjEXOWf (ORCPT ); Wed, 24 May 2023 10:22:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C34F512E; Wed, 24 May 2023 07:22:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6132563DD1; Wed, 24 May 2023 14:22:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE479C433D2; Wed, 24 May 2023 14:22:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684938153; bh=Ti7srOHrHydlQp6V2XYkCscD2SeIBeXLguWZIPuModw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FUdNlK6L8Loy0wWd0CgvfG/kzrVJSH6+DoP2oyLBHUy3mUEGYxjq1u5nRx7yhmf82 sWXfBZPdyAqklc7UG80vYzr5gbepP3tjP7RphgyzSOd462PuNQb9v+9RxpAuoxHEKm rLXLdpzBi7pbDwlCuOvp/XzJZDWjwn99U1veGzW8lPyYK4R/nRxAgW55BiN+Xw2x9z tmCjcfQhYUvYbUOW/8JsW7w7SjasRGRAGZU6mRPiILVz+nvvM85qFZzUMST1WAH3tv qYHd5WjW9GjgI3LuxZ2LZsxUTgT2BTnil8gQqptQgkuNSAa384KQoCDaYYbbulmijF HBE6/zmMN/f0w== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1q1pNv-0000eS-Pz; Wed, 24 May 2023 16:22:39 +0200 Date: Wed, 24 May 2023 16:22:39 +0200 From: Johan Hovold To: Dmitry Baryshkov Cc: Abhinav Kumar , Douglas Anderson , freedreno@lists.freedesktop.org, Rob Clark , Sean Paul , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, quic_jesszhan@quicinc.com, swboyd@chromium.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/msm/dp: add module parameter for PSR Message-ID: References: <20230427232848.5200-1-quic_abhinavk@quicinc.com> <053819bd-b3c4-a72c-9316-85d974082ad6@linaro.org> <4f2556e2-52ab-eb1d-b388-52546044f460@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4f2556e2-52ab-eb1d-b388-52546044f460@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 24, 2023 at 11:06:03AM +0300, Dmitry Baryshkov wrote: > On 24/05/2023 09:59, Johan Hovold wrote: > > Regressions happen and sometimes there are corner cases that are harder > > to find, but this is a breakage of a fundamental feature that was > > reported before the code was even merged into mainline. > > > >> We should have ideally gone with the modparam with the feature patches > >> itself knowing that it gets enabled for all sinks if PSR is supported. > > > > Modparams are things of the past should not be used to enable broken > > features so that some vendor can tick of their internal lists of > > features that have been "mainlined". > > We have had a history of using modparam with i915 and IIRC amdgpu / > radeon drivers to allow users to easily check whether new feature works > for their hardware. My current understanding is that PSR+VT works for on > some laptops and doesn't on some other laptops, which makes it a valid case. But here it does not seem to be the hardware that's the issue, but rather that the implementation is incorrect or incomplete. Johan